1. Field of Invention
The invention relates to a cover assembly used for a machine tool to prevent chips from flying and machining fluid from splashing outside the machine tool and also relates to an assembling method for such a cover assembly.
2. Description of Related Art
In a conventional machine tool, such as a machining center, a cover assembly is structured to enclose the machining area to prevent chips from flying and machining fluid from splashing outside the machine tool.
FIG. 6 shows an example of a conventional cover assembly. The cover assembly has a base 101. Formed at an upper portion of the base 101 is a mount 102 on which a machine tool is installed and into which a cover 103 is screwed. A peripheral wall 107 is provided vertically on a periphery of the mount 102. Accordingly, the upper portion of the base 101 is formed into a recess by the mount 102 and the peripheral wall 107. A space 104 of approximately 10 mm is formed between a peripheral plate 103a of the cover 103 and the peripheral wall 107. A packing 105 is squeezed into the space 104 from outside the cover 103 so as to prevent leakage of machining fluid or the like. The packing 105 is an elastic material, such as an urethane foam, having a thickness of approximately 15 mm. The packing 105 is compressed to a thickness of approximately 10 mm so as to be squeezed into the space 104.
The cover 103 has an extending portion 103b that extends outwardly from a mounting flange 103a to provide ample machining space. However, the extending portion 103b will cause a problem. The extending portion 103b becomes an obstacle to assembling/replacing the packing 105 and, as a result, considerable time and labor is required for mounting/dismounting the packing 105.
The base 101 and the cover 103 are 1000 mm to 1500 mm in diameter and may have a machining error of xc2x15 mm. Upon installation of the cover 103 having such a machining error on the base 101 also having such an error, variations in the amount of the space 104 may result. When the amount of space 104 is uneven from location to location, the packing 105 cannot be squeezed into the space 104 evenly. As a result, the upper surface of the packing 105 becomes unlevel and bad in appearance.
In another conventional cover assembly, the cover 103 is structured to extend vertically without an extending portion 103b, as shown by the dash-double dot lines. In this structure, the machining space is limited. Another problem with this structure is that a cosmetic cover 108 for hiding the packing 105 needs to be attached to the cover 103 to maintain a neat appearance.
In view of the foregoing problems, the invention provides a cover assembly, for a machine tool, that allows easy mounting/dismounting of a packing and has a neat appearance. The invention also provides an assembling method for such a cover assembly.
According to one preferred embodiment of the invention, a cover assembly used for a machine tool may include a base having a mount on an upper portion thereof and a peripheral wall provided on a periphery of the mount; a splash cover to be attached to the mount of the base; and a packing that seals a gap between the splash cover and the mount of the base. The splash cover and the mount of the base define an accommodating space therebetween, and the packing is placed in the accommodating space.
In this structure, the packing can be placed in the accommodating space and can be placed in and removed from the accommodating space easily without interference from the splash cover. In addition, because the packing is invisible from outside, the appearance of the splash cover is improved.
The splash cover may include a flange at a lower end thereof and may be attached to the mount of the base at the flange. In the structure, the packing can be placed in the accommodating space defined between the flange and the mount.
The flange of the splash cover preferably extends in an inward direction of the machine tool. The structure allows the packing to be placed in and removed from the accommodating space inside the machine tool without interference from the splash cover.
The mount of the base may include a stepped-down portion lower than a flange attaching portion of the mount. The accommodating space is defined between the stepped-down portion and the flange of the splash cover. In the structure, the packing can be positioned in the accommodating space defined between the stepped-down portion and the flange.
The stepped-down portion preferably includes a protrusion that prevents the packing from projecting from the accommodating space. In this structure, the packing is prevented from projecting and can be kept in place.
The cover assembly may further include a packing holder that prevents the packing from projecting from the accommodating space. In this structure, the packing is prevented from projecting and can be kept in place.
Further, it is preferable that the splash cover is assembled to the mount by a screw and the packing holder has a notch and is assembled to the mount together with the splash cover by the screw being inserted into the notch. This facilitates the assembly of the packing holder to the mount. The screw is initially loosely screwed into the mount to assemble the splash cover to the mount, the notch of the packing holder is fitted around the screw, and then the screw is securely screwed into the mount.
The packing is preferably hollow. This makes the packing more flexible and enables it to deform elastically so as to compensate for variations in size in the accommodating space. Accordingly, the packing provides an excellent sealing ability without being affected by variations in the size of the accommodating space.
Further, a plurality of slits are preferably formed in the packing. In this case, the packing, which is, for example, circular in cross section, elastically deforms along the slits into an oval shape in a stable manner. Thus, the packing stably makes intimate contact with the target surface, and the sealing ability of the packing is enhanced.
The cover assembly according to the invention is assembled by provisionally assembling the splash cover to the mount of the base so as to provide the accommodating space between the splash cover and the mount; inserting the packing into the accommodating space; and securing the splash cover to the mount. By this assembling method, the packing can be mounted easily without the need for being forcibly squeezed into the accommodating space.
When the cover assembly includes a packing holder with a notch, it is assembled by provisionally assembling the splash cover to the mount of the base by a screw so as to provide the accommodating space between the splash cover and the mount; inserting the packing into the accommodating space; fitting the notch of the packing holder around the screw; and securing the packing holder and the splash cover to the mount by the screw. By this assembly method, the packing can be mounted easily without the need for being forcibly squeezed into the accommodating space. In addition, the packing holder can be assembled easily at the same time together with the splash cover.